(a) Field of the Present Invention
The bi-directional light emitting diode drive circuit in bi-directional power series resonance is disclosed by that a first impedance is constituted by a capacitive component, and a second impedance is constituted by an inductive component, whereof they are in mutual series connection, and their inherent series resonance frequency is the same as the frequency or period of the bi-directional power source to generate a series resonance status. Thereof it is characterized in that when in series resonance, a bi-directional divided power is formed across the two ends of the capacitive impedance component and the inductive impedance component in mutual series connection, whereby the divided power is used to drive a bi-directional conducting light emitting diode which is either parallel connected with the first impedance or the second impedance, or at least two bi-directional light emitting diodes which are respectively parallel connected across the two ends of the first impedance and the second impedance are driven by the divided power across the two ends of the first impedance and the two ends of the second impedance.
(b) Description of the Prior Art
The conventional light emitting diode drive circuit using AC or DC power source is usually series connected with current limit resistors as the impedance to limit the current to the light emitting diode, whereof the voltage drop of the series connected resistive impedance always result in waste of power and accumulation of heat which are the imperfections.